Virology Flashcards
Which DNA virus family is not assembled in the nucleus?
Pox virus
Prototype of Poxviridae?
Variola (small pox)
Seven representatives of Herpes viridae?
- Herpes simplex virus 1 and 2
- EPV
- Cytomegalovirus
- Varicella-zoster
- Human Herpes virus 6
- Human Herpes virus 8 (Kaposi’s sarcoma)
Prototype of Adenoviridae?
Adenovirus
Prototype of Hepadnaviridae?
Hepatitis B virus
Prototype of Polyoma viridae?
JC virus
Prototype of Papilloma viridae?
Papilloma virus
Prototype of Parvoviridae?
Parvovirus B19
Structural components of icosahedral viruses in decreasing order of complexity:
- nucleocapsid is made of capsomeres
- capsomere (penton, hexon) is made of 5-6 protomers
What morphological type of virus is Tobacco Mosaic Virus?
helical nucleocapsid
What is the material called between the membrane of an enveloped virus and its nucleocapsid?
Tegument
What makes Type I complex viruses complex? Three examples?
- capsid is influenced by envelope arrangement
- Pox, Influenza, Arena viruses
What are two variations of Type II complex viruses? Examples of each?
- Lunar module (T2 bacteriophage)
- Bullet shaped (Rhabdo, Marburg viruses)
What is the latent period?
Time from the beginning of the infection until progeny virions are found outside the cell (once detected inside the cell, eclipse phase ends, but latent continues until virions detected outside the cell)
What types of proteins are produce in the early and late phases of viral replication?
- Early: proteins for replication
- Late: proteins for construction of virions
What are the receptor and co-receptors for HIV?
CD4
CCR5, CXCR4
What general virus types must bring their own polymerases to generate mRNA?
negative ss and ds RNA viruses
RNA dependent RNA polymerase
What is the attachment protein for adenovirus?
Fiber protein
What are the attachment proteins for herpesviridae?
gD and gB
What is the receptor and target cell for EBV?
- C3 complement receptor CR2
- B lymphocyte
What is the receptor and target cell for rhinovirus?
- ICAM-1
- epithelial cells
What is the receptor and target cell for rabies virus?
- acetylcholine receptor
- neuron
What is the receptor and target cell for influenza A virus?
- Sialyl oligosaccharides
- epithelial cells
What is the receptor and target cell for Herpes simplex virus?
- Heparan sulfate
- epithelial cells
In Pox viruses, what two enzymes are produced by early transcription?
- Uncoatase
- DNA polymerase
With Pox viruses, where does DNA replication take place?
- membrane-bound virosome (Guanieri’s body)
Picornavirus constitution, polarity, and primary gene product?
- continuous positive strand RNA
- large poly protein
Picornavirus prototype?
Poliovirus
Paramyxovirus constitution, polarity, and primary gene product?
- negative strand RNA
- multiple distinct mRNAs –> several different polypeptides
Paramyxovirus prototype?
Parainfluenza
Orthomyxovirus constitution, polarity, and primary gene product?
- small pieces of negative strand RNA
- multiple distinct mRNAs –> several different polypeptides
Orthomyxovirus prototype?
influenza virus
Reovirus constitution, polarity, and primary gene product?
- small pieces of dsRNA
- multiple distinct mRNAs –> several different peptides
What family does Polio, Rhino, Echo, and Coxsackie viridae belong to?
Picornaviruses
What family does measles, mumps, and respiratory syncytiovirus virus?
Paramyxoviruses
How does the Picornavirus polyprotein get cleaved?
- NCVPoo polyprotein is cleaved into NCVP1 and NCVPo
- NCVP1 is processed into capsid structural proteins
- — VPO, VP1, VP3 = procapsids
- — VP1, 2, 3, 4 = structural capsid proteins
- NCVPo is processed into non-structural proteins (RNA Pol)
- — NCVP1, 2, 4
Which NK receptor binds IgA?
Fc-alpha-RI (CD89)
Which NK receptor binds IgG?
Fc-gamma-RIII (CD16)
What three cytokines secreted by macrophages activate NK cells?
IL-12, IL-18, TNF
What cytokine is secreted by NK cells that activates macrophages?
TNF-gamma
What cytokine is absolutely required for NK cell development?
IL-15
How are NK cells inhibited?
Upon binding MHC I, the ITIM is phosphorylated and recruits phosphatases to counteract cellular activation
What three cells secrete Type I interferons? What stimulates secretion?
Macrophages, plasmacytoid DC’s, infected epithelial cell; binding of PRR’s on cells
What is the most potent releaser of IFN-Beta?
Plasmacytoid DC’s (PDC’s)
What is the difference between antigenic drift and shift in influenza?
Drift involves the emergence of point mutants with altered binding sites for protective Ab on the hemagglutinin
Shift involves reassortment of segmented RNA viral genomes of 2 different influenza viruses = LARGE hemagglutinin changes
Where does residual Herpes Simplex infection exist?
Trigeminal ganglion
Where does latent Herpes Zoster virus exist and what does re-emergence result in?
- dorsal root ganglia
- Shingles: rash appears in the area of skin served by the infected dorsal root (dermatome)
What disease does EBV cause? What is the result of a latent infection of EBV in B cells?
- infectious mononucleosis
- latently infected B cells can undergo malignant transformation giving rise to Burkitt’s Lymphoma (B cells)
What are two ways Hep C evades the immune system?
- interferes with DC activation and maturation via adaptive response in the liver
- high mutation rate (RNA Pol lacks proof reading)
How does lymphochoriomeningitis virus result in exhaustion of CD8 T cells?
- CD8 T cells express inhibitory receptors PD-1
- Virus makes ligand PD-L1 which binds the receptor and suppresses CD8 T cell effector function
Togavirus genome and constitution?
(+) ssRNA, enveloped icosahedral
4 alphavirus examples of Togavirus
Western Equine Encephalitis, EEE, Venezuelan EE, Chikungunya
Flavivirus genome and constitution?
(+) ssRNA, enveloped icosahedral
4 examples of Flavivirus?
St. Louis encephalitis, Dengue, Yellow Fever, West Nile
Bunyavirus genome and constitution?
(-) ssRNA, spherical enveloped (3 RNA containing nucleocapsids - L, M, S)
2 examples of Bunyavirus?
California virus, Hantavirus
Reovirus genome and constitution?
segmented dsRNA, spherical, unenveloped
2 examples of Reovirus?
Rotavirus, Colorado Tick Fever
Arenavirus genome and constitution?
enveloped virus
Bisegmented genome: L (-) ssRNA and S (-/+) RNA
2 examples of arenavirus?
Lassa fever (hemorrhagic) Lymphocytic choriomeningitis
Filovirus constitution and genome?
enveloped, helical
(-) ssRNA
2 examples of filovirus?
Marburg and Ebola hemorrhagic fevers
General constitution and genome of Herpesviruses?
- icosahderal enveloped (nuclear membrane) viruses
- Linear dsDNA
What are the 3 alpha herpes viruses? Lymphotropic or neurotropic?
- HSV-1, HSV-2, VZV
- neurotropic